I've tried everything.
Cranking the ISO (more noise means less compression), shooting detailed scenes, moving the camera a lot so the image is now fast moving and changing (ie less intra frame compression).
The best I get with 30p is 85mbps. And at 60p its funnily enough 170mbps. .... ie double the frame rate double the data rate...
Same test done the same way. I'd expect some variance but the fact 30p@200mbps is pretty much exactly half of 60p@200mbps.
So 30p@200mbps seems to pretty much have no hope of EVER recording at 200mbps and doesn't quite even hit 100mbps. Seems a bit wrong to me.